Recognising Possible Childhood Apraxia of Speech
When CAS Should Be Considered
Childhood Apraxia of Speech should be considered when a child has persistent speech difficulties that appear greater than would be expected from a typical speech delay or a straightforward articulation difficulty.
Concerns may arise when speech is very limited, difficult to understand, inconsistent or unusually effortful, particularly when the child appears to know what they want to say but has difficulty producing the required sequence of speech movements.
CAS should be considered as part of a wider assessment rather than assumed from one characteristic alone.
Delayed or Limited Speech
Some children with CAS may begin speaking later than expected or may have a much smaller spoken vocabulary than other children of a similar age.
They may produce:
- few recognisable words
- a limited range of consonants
- a restricted range of vowels
- only simple syllable shapes
- fewer spontaneous attempts at speech
Delayed speech is not specific to CAS and can occur for many reasons, but it may form part of the overall clinical picture.
Reduced Speech Intelligibility
Restricted Speech Sound and Syllable Repertoire
Children with CAS may be difficult to understand, particularly for people who do not know them well.
Intelligibility can be affected by:
- inaccurate consonants
- vowel errors
- disrupted sound transitions
- omitted sounds or syllables
- unusual stress
- slow or segmented speech
- inconsistent word production
It is useful to compare how well the child is understood by parents, teachers, peers and unfamiliar listeners.
Restricted Speech Sound and Syllable Repertoire
Restricted Speech Sound and Syllable Repertoire
A child with suspected CAS may use a smaller range of speech sounds and syllable structures than expected.
Assessment should consider:
- number of consonants used
- number and accuracy of vowels
- range of syllable shapes
- ability to combine different consonants and vowels
- ability to produce consonant clusters
- variety of word shapes
The child’s speech repertoire should be considered in relation to age, language level and the language or languages they speak.
Difficulty With Longer or Unfamiliar Words
Speech may become more difficult as words become longer or motorically more complex.
A child may produce short, familiar words relatively successfully but have increasing difficulty with:
- multisyllabic words
- unfamiliar vocabulary
- words containing several different speech movements
- consonant clusters
- longer phrases
This increase in errors as complexity rises can be useful during assessment.
Communication Intent and Attempts at Speech
For a meaningful motor speech assessment, the clinician needs opportunities to observe the child attempting to communicate through speech.
A child does not need to have extensive spoken language, but there should be enough intentional vocal or spoken attempts to examine how speech movements are being planned and produced.
For children with very limited speech, assessment may also use:
- play
- imitation
- parent interaction
- familiar routines
- home video
- vocalisations
- AAC and gesture alongside speech
Where there is not yet enough speech to make a confident diagnosis, the clinician may use a provisional description and review over time.
Differences Across Speaking Tasks
Differences Across Speaking Tasks
Speech performance may vary depending on what the child is being asked to do.
The clinician may compare:
- spontaneous speech
- imitation
- single words
- repeated words
- phrases
- connected speech
- familiar versus unfamiliar words
- supported versus unsupported production
A child should not be assessed from one task alone. Important characteristics may only become apparent when speech demands change.
Screening Is Not Diagnosis
Differences Across Speaking Tasks
Screening can help identify children who may need further assessment, but it cannot confirm CAS.
A screening tool may highlight:
- reduced intelligibility
- inconsistency
- restricted sound repertoire
- difficulty with complex words
- unusual prosody
- possible motor speech concerns
However, these features can occur in other speech sound disorders.
A diagnosis of CAS requires a more comprehensive assessment that examines speech across different tasks and considers alternative explanations.
Slow Progress in Therapy Is Not Diagnostic
A child should not be diagnosed with CAS simply because progress in previous speech therapy has been slow.
Limited progress can occur for many reasons, including:
- insufficient therapy intensity
- unsuitable treatment approach
- inconsistent attendance
- complex co-occurring needs
- hearing difficulties
- language difficulties
- severity of the speech disorder
Previous response to intervention can provide useful clinical information, but it should be considered alongside the wider assessment rather than used as evidence of CAS on its own.
When to Refer for Specialist Assessment
When to Refer for Specialist Assessment
Referral for specialist motor speech assessment should be considered when:
- speech is significantly difficult to understand
- speech development is markedly delayed
- the same words are produced differently across attempts
- longer words are disproportionately difficult
- speech appears effortful or segmented
- stress or rhythm sounds unusual
- the child has a very limited sound repertoire
- there is concern about speech motor planning
- the child has had limited progress despite appropriate intervention
- another professional has raised concern about possible CAS
Assessment should ideally be carried out by a Speech and Language Therapist or Speech Pathologist with experience in paediatric motor speech disorders.
Core Diagnostic Features of Childhood Apraxia of Speech
ASHA Consensus Features
Three speech characteristics are most consistently associated with Childhood Apraxia of Speech:
- inconsistent errors on consonants and vowels across repeated productions
- lengthened or disrupted transitions between sounds and syllables
- inappropriate prosody, particularly unusual stress patterns
These features are important, but they should not be treated as a simple checklist. Diagnosis depends on the overall speech pattern across more than one task.
Inconsistent Consonant and Vowel Errors
A child with CAS may produce the same word differently across repeated attempts.
Changes may involve:
- different consonant substitutions
- different vowel errors
- omission of different sounds
- changes in syllable structure
- variable accuracy from one attempt to the next
During assessment, repeated productions of the same words can help determine whether the child’s errors are stable or variable.
Inconsistency alone does not confirm CAS because it can also occur in other speech sound disorders.
Lengthened Coarticulatory Transitions
Disrupted Transitions Between Sounds and Syllables
Speech normally involves smooth and rapid movement from one sound to another.
In CAS, these transitions may be unusually prolonged. The child may appear to take extra time moving between articulatory positions.
This may be heard as:
- stretched transitions
- delayed movement between sounds
- unusually slow movement through a word
- reduced smoothness between syllables
These difficulties can become more obvious in longer or more complex words.
Disrupted Transitions Between Sounds and Syllables
Disrupted Transitions Between Sounds and Syllables
Some children show clear breaks in the flow of speech.
This may include:
- pauses within words
- separation of individual syllables
- disrupted consonant-vowel transitions
- repeated attempts to move into the next sound
- speech that sounds segmented or effortful
Assessment should consider whether these disruptions occur consistently across different tasks and levels of complexity.
Inappropriate Prosody and Stress
Vowel Distortions and Vowel Errors
Prosody includes stress, rhythm, timing, pitch and intonation.
Children with CAS may:
- stress the wrong syllable
- give syllables unusually equal stress
- pause in unexpected places
- use an unusual rhythm
- produce speech with reduced naturalness
- have difficulty adjusting stress across phrases and sentences
Prosodic differences are particularly important because inappropriate prosody is one of the three widely recognised consensus features of CAS.
Vowel Distortions and Vowel Errors
Vowel Distortions and Vowel Errors
Vowels should be assessed carefully rather than focusing only on consonants.
A child may:
- substitute one vowel for another
- produce a vowel that sounds distorted
- vary the vowel across repeated attempts
- have difficulty maintaining the correct vowel in longer words
Vowel distortions are clinically important because they may contribute to reduced intelligibility and can support a motor speech diagnosis when present alongside other CAS characteristics
Additional Motor Speech Features
Other characteristics may strengthen concern about CAS when they occur as part of the wider speech profile.
These can include:
Groping
Visible trial-and-error movements of the lips, tongue or jaw when attempting speech.
Schwa insertion
Adding a neutral vowel between consonants or syllables.
Segmented speech
Producing words as separate sounds or syllables rather than as a smooth sequence.
Slow speech rate
Speech may become unusually slow, particularly during difficult words or phrases.
Difficulty initiating speech
The child may hesitate before starting a word or appear to search for the correct articulatory position.
Voicing errors
Difficulty consistently producing voiced and voiceless consonants accurately.
Increasing errors with complexity
Speech may become less accurate as words become longer, less familiar or more complex.
These features are not unique to CAS and should not be interpreted in isolation.
Mayo 10+1 Features
Another diagnostic framework described in the CAS literature is the Mayo 10+1 feature set.
This approach considers a wider group of perceptual speech characteristics associated with CAS. Recent evidence summaries indicate that a pattern including vowel distortions together with several additional Mayo features across multiple speech tasks can contribute to diagnostic decision-making.
The value of this framework is that it encourages clinicians to look at a broad speech-motor profile rather than relying only on one or two characteristics.
Features Should Be Seen Across More Than One Task
Why No Single Feature Diagnoses Childhood Apraxia of Speech
A characteristic observed during one word or one assessment activity is not enough to establish CAS.
Assessment should look for patterns across several types of speech, such as:
- single words
- repeated words
- imitation
- multisyllabic words
- phrases
- spontaneous speech
- connected speech
Current evidence recommends using multiple speech tasks so that the clinician can determine whether motor speech features are consistent across different speaking demands.
Why No Single Feature Diagnoses Childhood Apraxia of Speech
Why No Single Feature Diagnoses Childhood Apraxia of Speech
Why No Single Feature Diagnoses Childhood Apraxia of Speech
There is no single symptom, test score or speech characteristic that proves a child has CAS.
Some children without CAS may show inconsistency, unusual prosody or difficulty with complex words. Likewise, a child with CAS may not display every commonly described characteristic in every situation.
Diagnosis therefore depends on the overall pattern across:
- consonants
- vowels
- transitions
- prosody
- word complexity
- repeated productions
- connected speech
- dynamic assessment
- functional intelligibility
- differential diagnosis
The strongest diagnosis comes from converging evidence across several assessment tasks rather than from one isolated finding.
Planning a Comprehensive CAS Assessment
Assessment by an Experienced Clinician
Childhood Apraxia of Speech should be assessed by a Speech and Language Therapist or Speech Pathologist with knowledge and experience of paediatric motor speech disorders.
CAS can be difficult to distinguish from other speech sound disorders, so the clinician needs to interpret the child’s speech pattern across a range of tasks rather than rely on a single score or checklist.
Tailoring the Assessment to the Child
Assessment should be adapted to the individual child rather than using exactly the same procedure for everyone.
The clinician should consider:
- age
- severity of speech difficulty
- amount of spoken language
- attention and tolerance for assessment
- developmental level
- language or languages spoken
- co-occurring conditions
- previous assessment and therapy
A younger or minimally verbal child will often need a very different assessment approach from an older child with mild residual CAS.
Use More Than One Speech Task
Assess More Than Speech Motor Planning
A comprehensive CAS assessment should include several different speaking tasks.
Current evidence supports using at least three speech tasks so that the clinician can compare performance under different levels of motor and linguistic demand.
Tasks may include:
- single words
- repeated word productions
- multisyllabic words
- imitation
- phrases
- connected speech
- rapid sequencing tasks
- dynamic motor speech tasks
This helps show whether suspected CAS features occur consistently across different contexts.
Assess More Than Speech Motor Planning
Assess More Than Speech Motor Planning
CAS assessment should not focus only on motor speech.
A broader assessment may also need to consider:
- receptive language
- expressive language
- phonological awareness
- literacy
- social communication
- hearing
- oral motor function
- functional communication
This is important because CAS can occur alongside other communication and developmental difficulties.
Hearing assessment
Hearing should be considered as part of the assessment process.
Even mild hearing difficulties can affect speech development, speech sound learning and intelligibility.
Where hearing has not been checked recently, referral for audiological assessment may be appropriate.
Hearing difficulties do not rule out CAS, and CAS and hearing loss can occur together.
Oral Structure and Movement
The clinician should examine the structures and movements involved in speech.
This may include:
- lips
- tongue
- jaw
- palate
- facial movement
- range of movement
- symmetry
- coordination
The purpose is partly to identify whether another motor speech disorder, such as dysarthria, may be contributing to the speech difficulty.
Non-speech oral motor difficulties should not be treated as proof of CAS.
Consider Age, Language, Accent and Culture
Assessment materials should be appropriate for the person’s linguistic and cultural background.
The clinician should consider:
- the child’s first language
- additional languages
- accent or dialect
- typical speech patterns in those languages
- language exposure
- cultural familiarity with assessment materials
A speech pattern that is typical in one language or dialect should not be misidentified as a disorder
Younger and Adults Need Different Assessment Tasks
Assessment should change as children become older and more verbally able.
For younger or more severely affected children, assessment may rely more on:
- play-based interaction
- simple words
- imitation
- dynamic assessment
- parent-child interaction
- vocalisations
- simple syllable structures
For adults,older or more mildly affected children, assessment should place greater demands on the speech motor system through:
- polysyllabic words
- unfamiliar words
- rapid speech sequencing
- connected speech
- reading aloud
- longer utterances
Residual CAS can be missed if assessment tasks are too easy.
The CAS Assessment Process
Observing Natural Communication
Observe the child interacting naturally with a parent, carer or clinician to see how speech functions outside structured testing.
Connected Speech Sampling
Collect conversation, story retell, picture description or play-based speech to examine accuracy when the child has to plan continuous speech. The 2026 evidence brief specifically recommends connected-speech samples as part of CAS assessment.
Comparing Structured and Spontaneous Speech
Compare performance when the child repeats a clinician's model with speech they generate independently.
Increasing Linguistic Demand
Move from straightforward utterances to sentences, narratives or more complex language to examine whether speech changes as formulation and motor-planning demands increase.
Recording a Representative Sample
Audio or video recording allows detailed analysis after the session and provides a baseline for future comparison.
Phonetic Transcription
Use narrow or broad phonetic transcription where appropriate to document distortions, substitutions, omissions and unusual vowel productions accurately.
Assessment Tools and Measures
Childhood Apraxia of Speech Assessment Tools and Measures
No single assessment tool can diagnose Childhood Apraxia of Speech on its own. Tools and structured tasks should be used as part of a wider motor speech assessment and interpreted alongside connected speech, prosody, inconsistency, dynamic assessment and differential diagnosis.
Dynamic Evaluation of Motor Speech Skill (DEMSS)
DEMSS is a dynamic motor speech assessment designed particularly for children with severe speech disorders or limited speech output. It examines articulatory accuracy, vowel accuracy, prosody, consistency and how the child responds to different levels of cueing.
It is particularly useful where standard articulation testing does not provide enough information about speech motor planning.
Reference:
Strand, E. A. and McCauley, R. J. (2019). Dynamic Evaluation of Motor Speech Skill (DEMSS) Manual. Windsor Mill, MD: Brookes Publishing.
Validation study:
Strand, E. A., McCauley, R. J., Weigand, S. D., Stoeckel, R. E. and Baas, B. S. (2013). ‘A motor speech assessment for children with severe speech disorders: Reliability and validity evidence’, Journal of Speech, Language, and Hearing Research, 56, pp. 505–520.
Nuffield Dyspraxia Programme Assessment
The Nuffield Dyspraxia Programme (NDP3) includes structured assessment of speech sound production, syllable structures and increasingly complex speech sequences.
It can contribute useful information about the child’s speech repertoire and the level of complexity at which difficulties become more apparent.
It should be used as part of a wider assessment rather than as a stand-alone diagnostic test for CAS.
Reference:
Williams, P. and Stephens, H. (2009). The Nuffield Dyspraxia Programme.
Website:
http://www.ndp3.org/
Verbal Motor Production Assessment for Children – Revised (VMPAC-R)
The Nuffield Dyspraxia Programme (NDP3) includes structured assessment of speech sound production, syllable structures and increasingly complex speech sequences.
It can contribute useful information about the child’s speech repertoire and the level of complexity at which difficulties become more apparent.
It should be used as part of a wider assessment rather than as a stand-alone diagnostic test for CAS.
Reference:
Williams, P. and Stephens, H. (2009). The Nuffield Dyspraxia Programme.
Website:
http://www.ndp3.org/
Diagnostic Evaluation of Articulation and Phonology (DEAP)
The DEAP is a standardised assessment of articulation and phonology.
Its inconsistency component can be particularly useful when distinguishing CAS from inconsistent phonological disorder, because inconsistency by itself does not establish a diagnosis of CAS.
DEAP does not diagnose CAS, but it can provide valuable information for differential diagnosis.
Reference:
Dodd, B., Hua, Z., Crosbie, S., Holm, A. and Ozanne, A. (2002). Diagnostic Evaluation of Articulation and Phonology (DEAP). London: The Psychological Corporation.
Website:
https://www.pearsonclinical.co.uk
In the video Lorraine Bamblet (Friend of Speech Apraxia) demonstrates the practical application of the DEAP assessment to diagnose specific speech sound disorder subtypes in children. This guide details how to navigate the picture stimulus book, record phonetic transcriptions, and utilize subtests to differentiate between phonological, articulation, and inconsistency difficulties
Syllable Repetition Task (SRT)
The Syllable Repetition Task uses simple nonword syllables to examine speech processing, memory and sequencing while reducing the influence of a child’s previously learned speech errors.
It can provide useful additional information when evaluating children with complex speech sound disorders, particularly older or more verbal children.
It is a complementary assessment task rather than a CAS diagnostic test.
Reference:
Shriberg, L. D., Lohmeier, H. L., Campbell, T. F., Dollaghan, C. A., Green, J. R. and Moore, C. A. (2009). ‘A nonword repetition task for speakers with misarticulations: The Syllable Repetition Task (SRT)’, Journal of Speech, Language, and Hearing Research, 52(5), pp. 1189–1212.
Full text:
https://pmc.ncbi.nlm.nih.gov/articles/PMC3875157/
THE SYLLABLE REPETITION TASK (SRT) Technical Report No. 14 Lawrence D. Shriberg Heather L. Lohmeier
http//:phonology.waisman.wisc.edu/wp-content/uploads/sites/532/2018/05/TREP14.pdf
Maximum Repetition Rate and Diadochokinetic Tasks
Maximum repetition rate and diadochokinetic tasks involve rapid repetition of syllables or syllable sequences.
These tasks can provide information about speech motor sequencing, coordination and rate, particularly in older children.
Results need to be interpreted carefully because performance is influenced by age, speech accuracy and the child’s ability to understand and complete the task. Poor performance is not specific to CAS.
Reference:
Diepeveen, S., van Haaften, L., Terband, H., de Swart, B. and Maassen, B. (2019). ‘A standardized protocol for maximum repetition rate assessment in children’, Folia Phoniatrica et Logopaedica, 71(5–6), pp. 238–250.
Full text:
https://pmc.ncbi.nlm.nih.gov/articles/PMC7050664/
Intelligibility in Context Scale (ICS)
The Intelligibility in Context Scale is a short parent-report measure that examines how well a child is understood by different people in everyday life.
It considers communication with:
- parents
- immediate family
- extended family
- friends
- teachers
- acquaintances
- strangers
The ICS does not diagnose CAS, but it provides valuable information about the functional impact of the child’s speech difficulties and can complement impairment-based motor speech assessment.
Reference:
McLeod, S., Harrison, L. J. and McCormack, J. (2012). ‘The Intelligibility in Context Scale: Validity and reliability of a subjective rating measure’, Journal of Speech, Language, and Hearing Research, 55(2), pp. 648–656.
Website:
https://www.csu.edu.au/research/multilingual-speech/ics
Using Assessment Tools Appropriately
The tools above have different purposes.
Named assessment instruments:
DEMSS, VMPAC-R, NDP3 and DEAP.
Complementary assessment measures and tasks:
Syllable Repetition Task, maximum repetition rate, polysyllabic speech tasks and the Intelligibility in Context Scale.
None should be presented as a stand-alone “CAS test”. The strongest assessment combines several sources of evidence and examines the child across different speech tasks and communication situations.
Key Research Supporting Comprehensive CAS
Differential diagnosis of children with suspected childhood apraxia of speech.
Murray, E., McCabe, P., Heard, R. and Ballard, K. J. (2015).
.Journal of Speech, Language, and Hearing Research, 58(1), 43–60.
This study examined which assessment measures best distinguished CAS from other speech disorders. It found that a combination of measures, including syllable segregation, lexical stress, polysyllabic speech accuracy and rapid syllable sequencing, provided strong diagnostic value. It supports using multiple complementary speech tasks rather than relying on one test or feature.
https://pubmed.ncbi.nlm.nih.gov/25480674
Dynamic Evaluation of Motor Speech Skill (DEMSS) Manual
Strand, E. A. and McCauley, R. J. (2019).
Baltimore, MD: Brookes Publishing.
DEMSS is a dynamic motor speech assessment particularly useful for children with severe or limited speech. It examines how speech changes with cueing and support, helping clinicians assess motor planning, severity and differential diagnosis. It is especially useful when standardised articulation testing does not provide enough information.
https://brookespublishing.com/product/demss
Speech inconsistency in children with Childhood Apraxia of Speech, language impairment, and speech delay: Depends on the stimuli.
Iuzzini-Seigel, J., Hogan, T. P. and Green, J. R. (2017Journal of Speech, Language, and Hearing Research, 60(5), 1194–1210.
This study showed that inconsistency can help distinguish CAS from other speech disorders, but its usefulness depends on the words and tasks used. It supports assessing inconsistency across carefully selected and varied speech stimuli, rather than treating inconsistency alone as diagnostic of CAS.
https://pubmed.ncbi.nlm.nih.gov/28395359/
A tool for differential diagnosis of Childhood Apraxia of Speech and dysarthria in children: A tutorial. Language, Speech, and Hearing Services in Schools
Iuzzini-Seigel, J., Allison, K. M. and Stoeckel, R. (2022).
53(4), 926–946.
This paper introduces the Profile of Childhood Apraxia of Speech and Dysarthria (ProCAD), a structured approach to distinguishing CAS from childhood dysarthria. It considers articulatory, prosodic, phonatory, respiratory and resonatory features across multiple speech tasks and is particularly useful when a mixed motor speech disorder is suspected.
https://epublications.marquette.edu/spaud_fac/66/